Blade assembly for wiping motor vehicle windscreens

ABSTRACT

A wiper blade serves to wipe motor vehicle windows. The wiper blade has an elongated wiping strip contacting the window and a holder which grasps the longitudinal sides of the wiping strip by at least two claws arranged at clip-like frame parts and a securing member which is fixed in the vicinity of one end of the wiping strip crosses the claws with two arms extending roughly parallel to one another and engages behind the claws by securing means. A worn wiping strip may be removed and replaced in a simple manner in that the securing member has a base part which is U-shaped in cross section and can be slipped onto the end of the wiping strip so as to fit thereon accompanied by clamping, in that at least the arms of the securing member are made of a flexible plastic, and in that securing means having locking or catching means are provided at the free end portion of one arm, complementary locking means of the other arm being associated with the securing means.

PRIOR ART

The invention concerns a wiper blade. In a known wiper blade, asdisclosed in German patent 21 54 863 A, during the insertion of thewiping strip into the claws of the holder, a securing element mounted onthe wiper strip end engages with its elastically deflectable arms overthe claws of the holder and the arms spring behind the claws. The armsarrestingly engage the claws with their arresting projections providedon their free ends and operating as securing means. Since the arms whichmust apply the whole arresting force are relatively short in alongitudinal direction, a great deviating angle under consideration ofthe arresting projections is provided. This arresting angle can berealized only with maintaining of very narrow tolerances both on theholder and on the claws as well as on the securing element, sinceotherwise there is a danger of breaking the arms. Also, the arms due totheir available manufacturing stresses can spread, so that the lockingis not sufficient or is not provided at all.

SUMMARY OF THE INVENTION

The wiper blade according to the invention with the characterizingfeatures of the main claim has the advantage over the prior art that thebase part can be clamped at the wiper blade in a self-locking mannerresulting in a preassembled unit which can easily be connected with theholding clip frame as needed. Owing to the flexible arms of a safetyelement which is composed of a relatively soft synthetic plasticmaterial, the securing means can easily be guided around the back of theclaws then both arms are directly connected with one another by thesecuring means behind the holding frame or the claw by means of thelocking and counterlocking means, so as to provide an especially securemounting of the wiping strip on the holder. There is no need for specialdirections for assembling and operating the locking means, since theirmanner of operation may be understood by observation alone.

Advantageous further developments and improvements of the wiper bladeindicated in the main claim are made possible by the steps indicated inthe subclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment example of the invention is shown in the drawing andexplained in more detail in the following description.

FIG. 1 shows a perspective view of a fully assembled wiper blade;

FIG. 2 shows an enlarged partial view of the end portion of a wiperblade as viewed in the direction of arrow II in FIG. 1;

FIG. 3 shows a partial section through the wiper blade according to FIG.2 along line III--III;

FIG. 4 shows a partial view of two spring bars of the wiper blade;

FIG. 5 is an enlarged view showing a cross section through the wiperblade along line V--V in FIG. 2;

FIG. 6 shows a cross section according to FIG. 5 through a wiping stripof the wilder blade in which are installed the two spring bars accordingto FIG. 4;

FIG. 7 shows a partial longitudinal section along line VII--VII in FIG.8 through a securing member belonging to the wiper blade;

FIG. 8 shows a cross section through the securing member according toFIG. 7 along line VIII--VIII;

FIG. 9 shows a partial section through the securing member according toFIG. 7 along line IX--IX;

FIG. 10 shows a partial section through the securing member according toFIG. 7 along line X--X;

FIG. 11 shows a section through the locked securing means along lineXI--XI in FIG. 3;

FIG. 12 is an enlarged view of a detail XII in FIG. 11.

DESCRIPTION OF THE PREFERRED EMBODIMENT

At the present time, it is increasingly common to provide so-calledrefills for wiper blades of the type shown in FIG. 1. These refills areused to replace wiping strips which have been damaged through use. Arefill has an elongated wiping strip and spring bars which areaccommodated in the wiping strip as pressure distributing means andextend substantially along the entire length of the wiping strip.Further, such refills include at least one securing member which securesthe wiping strip on a clip holder. In this way the wiping strip which isheld by the claws of the holding clip frame is prevented from creepingout of these retaining claws in the longitudinal direction. Further,this securing member also often serves to lock the spring bars at thewiping strip. Often, it is very complicated to assemble the knownrefills, as has been established to the annoyance of the layman. This isdue in part to the fact that such a refill has four loose components(wiping strip, two spring bars and a securing member) and the functionof the securing member and position for installing the spring bar canonly be found after extended trial attempts or by reading relativelyextensive directions for assembly.

A wiper blade 10 shown in FIG. 1 has a holding clip frame 12 formed by aplurality of frame parts 14. The frame parts have retaining claws 16through which a so-called refill 18 is guided. The refill 18 has thesame kind of elongated shape as the holding clip frame 12. Eachretaining claw 16 grips the longitudinal sides of a wiping strip whichforms part of the refill 18. A securing member 22 of the refill servesto fix the refill 18 at the holding clip frame 12. The securing member22 has a base part 24 from which two arms 26 and 28 extend substantiallyparallel to one another. The arms 26 and 28 cross and overlap the claw16 of the holding clip frame 12, which claw 16 is located in thevicinity of one end of the wiping strip 20. Securing means 30 whichengage behind this retaining claw 16 or behind the frame part 14belonging to the retaining claw are arranged at the free ends of thearms 26 and 28. This arrangement is shown particularly in FIGS. 2 and 3.In the embodiment example, the securing member 22 is produced in itsentirety from a flexible plastic, i.e. the arms 26 and 28 and thesecuring means 30 are connected with the base part 24 so as to form onepiece.

As is illustrated in FIG. 6, the wiping strip 20 has a head strip 32 andan elongated wiper lip 34. The head strip and wiping strip are connectedwith one another via an elongated wobbling web 36. The wiping strip 20has a uniform cross section along its entire length so that it can bemanufactured advantageously by extrusion so as to provide an inexpensiverefill. The wiping strip 20 is symmetrical in cross sectioncorresponding to FIG. 6. Accordingly, with reference to an axis 38 ofsymmetry, two longitudinal grooves 40 which serve to receive spring bars42 are arranged opposite one another in the head strip 32. As a resultof these spring bars 42, the contact pressure acting on the wiper bladeis uniformly distributed on the windshield to be wiped. The spring bars42 are shown in FIG. 4. They are shown in their assembled position inFIG. 6. The spring bars 42 have cut out portions 44 which open towardthe edge and are arranged at the outside of the spring bars 42 close toone end so as to lie opposite one another as viewed in the longitudinaldirection. As is shown in particular by FIGS. 5 and 8, the base part 24of the securing member 22 is substantially U-shaped in cross section.Thus, it has two sides or legs 46 and 48 and a wall 50 connecting thetwo legs of the U. A sawtooth-shaped, inwardly projecting clampingshoulder 52 is arranged at the wall 50 in such a way that the securingmember 22 cannot disengage from its assembled position which will bedescribed in the following.

Sawtooth-shaped retaining teeth 54 and 56 which engage in the cut outportions 44 of the spring bars 42 in preassembled refills (FIG. 5) arelocated at the two U-legs 46 and 48 of the base part 24 at the sides ofthe U-legs facing one another. A strip-like projection 60, 62 (FIG. 8)is arranged at the free U-legs 46, 48 of the base part 24 which isU-shaped in cross section. The strip-like projections 60 and 62 aredirected toward one another and penetrate into channels 64, 66 of thehead strip 32 when the securing member 22 is assembled, these channels64, 66 being shaped like longitudinal grooves (FIG. 5). The arms 26 and28 of the securing member 22 extend from the base part 24 of thesecuring member 22 in the slip-on direction (arrow 68, FIG. 3) of thesecuring member 22 when the latter is slipped onto the head strip 32 ofthe wiping strip 20. The head strip and base part are so dimensionedthat the securing member 22 can be attached with the desired degree ofclamping. In so doing, the retaining teeth 54 and 56 enter the cut outportions 44 of the spring bars 42 which are already inserted. Further,the clamping shoulder 52 penetrates into the head strip 32 of the wipingstrip 20 which is made of a rubber-like material (FIG. 5). The securingmember 22 is slid onto the head strip 32 until an end wall 70 which islocated at the end of the base part 24 remote of the arms and connectsthe two U-legs 46 and 48 of the base part 24 abuts at the head strip 32.

The securing means 30 will be described more fully in the following.These securing means 30 include a transverse tab 72 at the free end ofthe arm 28, which transverse tab 72 extends to the other arm 26 when thesecuring member is assembled. This transverse tab 72 has an opening 74which is shown as square in the embodiment example. The securing meansalso include a lateral step 76 at the other arm 26. This step 76 isconstructed and adapted in such a way that it can engage in the opening74. As is shown in FIG. 12, the opening 74 has, at its side remote ofthe arm 28, a wall region having an undercut which acts as a securingdevice and is constructed at an angle α. This undercut (angle α) isadapted to the shape of the side cheek region 78 of the step 76. Thisoffers a degree of protection against an unintentional opening of thecatch connection formed by the opening 74 and the step 76 of the twoarms 26 and 28.

Accordingly, in the preassembled refill, the base part 24 of thesecuring member 22 holds the preassembled refill together since thesecuring member is held at the head strip of the wiping strip 20 atleast via the clamping shoulder 52. The retaining teeth 56 and 54 securethe spring bars 42 by their cut out portions 44 so as to prevent anunintentional disengagement of the wiping strip 20. Thus, the user ofthe refill need only thread the preassembled refill through the claws 16of the holding clip frame 12 until the base part 24 abuts at the claw ofthe frame part 14 by one of its end edges 80 (FIG. 7). It then guidesthe arms 26, 28 outwardly past the claw 16 and frame part 14 until thetransverse tab 72 engages behind the claw 16 and frame part 14 assecuring means (FIGS. 2 and 3). The step 76 then engages in the opening74 of the transverse tab 72. In this way, the wiping strip 20 isadequately secured at the holding clip frame 12.

We claim:
 1. A wiper blade for wiping windows of motor vehicles, thewiper blade comprising an elongated wiping strip for contacting a windowand having longitudinal sides and two ends; a holding frame having frameparts connected thereto, said frame parts provided with claws forlongitudinally, slidably receiving said strip, said claws grasp saidlongitudinal sides of said wiping strip; an elongated securing memberfor longitudinally fixing one end of said wiping strip with one of saidframe parts, said securing member has two arms which overlap a claw ofsaid one frame part and extend substantially parallel to one another,said securing member having securing means on said arms for engagingbehind said claw of said one frame part, said securing member alsohaving a base part from which said arms extend, said base part beingU-shaped in transverse cross section and slippable onto an end of saidwiping strip such that said base is secured with said wiping strip, atleast said arms of said securing member being composed of a flexibleplastic, said securing means including a first locking element providedat a free end of one of said arms and a complementary second lockingelement provided at a free end on the other of said arms and cooperatingwith said first locking element to lock said wiping strip at said oneframe part, a locking connection is established between said firstlocking element and said complimentary second locking element such thatsaid securing member surrounds said claw of said one frame part tosecure said wiping strip with said one frame part.
 2. A wiper blade asdefined in claim 1, wherein said wiping strip is comprised of anelongated head strip, an elongated wiping lip, and a connecting memberconnecting said elongated wiping lip with said head strip, said headstrip having two longitudinal grooves located opposite one another withreference to an axis of symmetry of said wiping; and said wiping stripfurther comprising elongated spring bars located in said longitudinalgrooves, said spring bars having cutout portions therein which open awayfrom one another at outer sides of said spring bars, said U-shaped basepart of said securing member including legs with mutually facing sideswhich are provided with retaining teeth thereon engaging in said cutoutportions.
 3. A wiper blade as defined in claim 2, wherein saidconnecting member is formed as a web.
 4. A wiper blade as defined inclaim 2, wherein said connecting member is formed as a cross-piece.
 5. Awiper blade as defined in claim 2, wherein said head strip haslongitudinally extending channels formed therein in addition to saidgrooves, said legs having free ends provided with projections which faceone another and engage in said channels of said head strip.
 6. A wiperblade as defined in claim 1, wherein said U-shaped base part includeslegs and a wall which connects said legs said wall has an inwardlyprojecting clamping shoulder.
 7. A wiper blade as defined in claim 1,wherein said securing member is mountable in an a longitudinal directiondefined by said strip, said arms extending from said base part in saidlongitudinal direction, said base part having legs and an end wallconnecting said legs, said end wall provided at an end of said base partremote from said arms.
 8. A wiper blade as defined in claim 1, whereinsaid first locking element includes a transverse web provided at saidend of said one arm, said web having an opening therein, saidcomplimentary second locking element being formed by a lateral stepprovided at said end of said other arm and fitting into said opening. 9.A wiper blade as defined in claim 8, wherein said opening at a sideremote from said one arm has a wall region having an undercut formingpart of said securing means.
 10. A wiper blade as defined in claim 9,wherein said step has a side cheek region with a shape corresponding toa shape of said undercut.
 11. A wiper blade as defined in claim 1,wherein said arms and securing means are formed of flexible plastic andare formed as a one piece structure.